Plasma vs. LCD: Six things you need to know

updated A while ago, a friend sent me the following email:

The question wasn't as random as he supposed; I've been receiving similar queries from other friends and readers regularly. The great marketing machines of Philips, Sony, and Samsung have combined with major electronics retailers to work everybody into a flat-panel frenzy -- even people who say they don't watch TV. The only problem, of course, is that there happen to be two kinds of flat panels, and both have their pluses and minuses. With that in mind, I've put together a quick rundown of what you should know before going the plasma or LCD route, along with a few pointers.

1. Price-to-size ratio

While neither LCD nor plasma TVs are a budget bargain, on a price-per-square-inch basis, plasmas currently have a slight edge. Look at it this way: Technically, a 42-inch plasma gives you approximately 30 percent extra screen real estate as a 37-inch LCD panel, but they both go for about AU$2000. Prices have almost halved in the last twelve months, but larger versions (50 inches or more) won't cost the same as their plasma equivalents for quite a while.

The reason my friend was looking at a 20-inch TV for his bedroom is that prices for smaller LCD panels at the time were dropping the fastest, with a 20-incher coming in at a little more than AU$1,200. Today, 26 inches are about the smallest the mainstream manufacturers sell and they are available for about the same price. Plasmas aren't available in that size; 32 inches is their lower limit. Just remember that a 20-inch screen is pretty small, and you'll have to sit rather close to it. It may be fine for viewing the news and sitcoms in bed, but it's obviously less than ideal for enjoying movies. And a 17-inch model should be reserved for use as a kitchen television or a computer monitor in a home office; while you work, you can watch TV in a little picture-in-picture box in a corner of the display.

Bottom line: 32-inch LCDs offer the greatest value among bedroom sets, and your best bet for the living room is a 40-inch or larger LCD or plasma.

2. Performance
A general rule of thumb is that plasmas deliver better home theatre performance than LCDs. Our video guru, David Katzmaier, says the difference is due mostly to the fact that backlighting-based LCD TVs typically can't display black as well as plasmas; it ends up closer to dark grey. That shortcoming decreases the amount of detail you can see in the shadows and ultimately leaves the picture looking -- as videophiles would say -- less three-dimensional.

The picture quality of both LCD and plasma panels is improving each year, but it can vary significantly from manufacturer to manufacturer, so check our lists of top products. We're nitpicky about performance in our reviews -- it's our job -- and you should seriously consider our evaluations if you plan on using your set for home theatre viewing. But if you're buying a smaller LCD (26 inches or less) for the kitchen or the bedroom, don't agonise too much over performance.

3. Lifespan
Lifespan, the number of viewing hours a television provides before dimming to half brightness, used to be one of the biggest advantages LCD has over plasma. Though the numbers vary among the different brands, they now generally last up to around 60,000 hours regardless of the technology.

4. Burning issues
One of plasma technology's known issues is something called burn-in. It happens when your television shows a still image or an icon for so long that its "ghost" remains on the screen. For example, if a stock ticker or a news crawl continuously runs along the bottom of your display, that strip may be burned into your set. The same applies to watching an excessive amount of standard TV (4:3) on a widescreen (16:9) model; the vertical bars to either side of the picture could become permanent. Manufacturers have taken steps to prevent burn-in, building in screensavers and other technologies. And you can virtually eliminate the danger by not leaving still images on the screen and reducing your contrast setting below 50 percent for the first 100 hours of usage.

To their credit, LCDs don't suffer from burn-in, nor do they have troubles at high altitudes where the air pressure differential causes plasmas to emit an irritating buzzing sound. So, if you live in mountainous regions, we don't recommend that you get a plasma, though some manufacturers are selling special sets they claim are immune to the problem.

5. Viewing HDTV
Most plasmas and LCDs can display a high-def signal. However, you'll need a model with a resolution of at least 1,280 x 720-pixel to enjoy the full effects of HD. Most 50-inch plasmas and nearly all 32-inch and larger LCDs offer this resolution. Several new 42-inch plasmas now do, but when you're watching HD feeds on a lower-resolution television of that size or smaller, you'll have to sit much closer to notice much of a difference between HD and what you're seeing. Take Pioneer's PDP-427XG. Even though the set provides only XGA resolution (1,024 x 768), HDTV looks really good on it.

6. Computers and video games
Most plasma and LCD TVs can double as computer monitors; some even offer a DVI or D-Sub port for optimal video quality. They'll also hook up to a game console without any problems. So which technology is better for these purposes? From a performance standpoint, it's hard to pick a winner, but because of plasma's burn-in risk, LCD is the safer choice for computer work and gaming.